1. Field of the Invention
The present invention relates to recording/playback apparatuses, recording methods, playback methods, and programs. More particularly, the invention relates to a recording/playback apparatus, a recording method, a playback method, and a program, which are suitable for recording two formats of coded data having different amounts of data on a predetermined recording medium.
2. Description of the Related Art
Technologies for recording or playing back video data and audio data on or from optical discs are known. For example, the following technology is disclosed in Japanese Unexamined Patent Application Publication No. 11-136631. In a field editing system for editing video signals captured by a television camera in a shooting site, when recording video data and audio data on an optical disc, two formats of coded data having different amounts of data are generated and recorded on an optical disc so that management of materials or editing operations can be simplified.
In the above-described technology, raw video and audio data are coded by being compressed into two formats of coded data having different amounts of data, and are temporarily stored in a large-capacity memory (buffer), and are then stored in an optical disc.
More specifically, it is now considered that the above-described technology is used in a recording/playback apparatus for recording or playing back data on or from a recording medium, such as an optical disc. For example, as shown in FIG. 1, a baseband signal is coded in a codec 1 by being compressed into two formats of coded data having different amounts of data, and the two formats of coded data are supplied to a compressed-data buffer 2 and are then stored in a predetermined recording medium, such as an optical disc. In this case, the codec 1 is operated based on the system clock of the baseband signal, and the time when the two formats of compressed data are supplied to the compressed-data buffer 2 is also controlled by the system clock of the baseband signal. However, the time when the two formats of data are recorded on the predetermined recording medium from the compressed-data buffer 2 is not determined by the system clock of the baseband signal. For example, even when the processing time at which the data is recorded on the predetermined recording medium is much faster than the system clock of the baseband signal, the processing for recording the compressed data on a recording medium is not disturbed by controlling the time at which the data is read from the compressed-data buffer 2.
When reading data from a predetermined recording medium, such as an optical disc, the coded data is supplied to the compressed-data buffer 2, and is read at a rate corresponding to the processing rate of the codec 1. The codec 1 then performs decoding processing by using the system clock of the baseband signal and outputs a non-compressed baseband signal. That is, even when the reading speed for the data recorded on a predetermined recording medium is faster than the processing rate of the codec 1, in other words, even when the system clock for controlling the reading processing for data recorded on a predetermined recording medium, such as a disc, is faster than the system clock of the baseband signal, the processing of the codec 1 is not disturbed by controlling the time at which the data is read from the compressed-data buffer 2. As a result, the baseband signal having continuous frames can be output.